LONDON — Two assailants hacked a man to death on a busy southeast London street Wednesday afternoon before delivering a rant about Islam to bystanders, leading Prime Minister David Cameron to cut short a diplomatic trip to Paris to deal with what he described as a likely terrorist attack.

If confirmed as an act of terrorism, it would be the first fatal attack in Britain since 52 people were killed in four coordinated suicide bombings targeting London’s transit system on July 7, 2005. Both suspects in Wednesday’s attack — who made no attempt to escape and shouted statements at bystanders while waiting for authorities to arrive — were wounded by police as they were taken into custody and were being treated at local hospitals. At least one of the men was in serious condition, and both were under armed guard.

British news media outlets reported that the victim was a British soldier wearing the shirt of Help for Heroes, a charity that helps British service members injured in combat. Neither Scotland Yard nor government officials immediately confirmed the reports, but Nick Raynsford, a legislator from the Woolwich neighborhood where the attack occurred, told the BBC that the man killed was a soldier serving at a nearby army barracks.

Britain immediately moved to increase security around various military installations. Meanwhile, Britons were shocked by snippets of videos filmed by bystanders. One amateur video obtained by London’s ITV television showed one of the alleged assailants — a man holding two bloody blades and whose hands appear to be covered with blood — shouting in English.

“There are many, many ayah throughout the Koran,” the man says in the video, referring to religious verses, “that says we must fight them as they fight us, an eye for an eye and a tooth for a tooth. I apologize that women had to witness this today, but in our land women have to see the same. You people will never be safe. Remove your government; they don’t care about you.”

According to the TV network, in a segment of the film that was not broadcast, the man also says, “We swear by almighty Allah we will never stop fighting you.”

Speaking in Paris, Cameron said there were “strong indications that this is a terrorist incident.” He was poised to chair a national security meeting Thursday morning.

“The killing in Woolwich is truly shocking,” Cameron said, later adding, “We’ve had these sorts of attacks before in our country, and we will never buckle in the face of them.”

British authorities were scrambling to ascertain whether the men had acted alone, whether they were homegrown militants or whether they were associated with overseas Islamist extremist groups. Britain, the leading U.S. ally in Afghanistan, has confronted several terrorism plots and has launched a national program aimed at de-radicalizing youths who are at risk. In February, three men from Birmingham were convicted in a courthouse near the site of Wednesday’s attack of plotting suicide bombings to rival the deadly 2005 blasts.

Metropolitan Police Commander Simon Letchford said that the first reports of an incident came around 2:20 p.m. and that they indicated a man was being assaulted by two men near an elementary school. He said a number of weapons were reported being used in the attack, including a firearm.

“Two men, who we believe from early reports to have been carrying weapons, were shot by police,” Letchford said. “They were taken to separate London hospitals. They are receiving treatment for their injuries.”

Witnesses suggested that the men had first hit the victim with a vehicle before attacking him with knives. Some reports indicated that the attackers had yelled “God is great” in Arabic before wildly stabbing at the victim, with conflicting accounts on whether they had tried to behead him. The men encouraged passengers on a bus to photograph them and film them with phone cameras, leading to a number of chilling videos and photos posted online. The attack occurred near a school, and local television showed children unnerved by the mayhem. The men, walking around bloody and shouting after the attack, apparently allowed only women to approach the body before police arrived.

A 48-year-old woman, Ingrid Layou-Kennett, approached one of the men just after the attack, engaging him in conversation in an attempt to aid the victim, the Telegraph reported. A published photograph showed the woman speaking to the assailant as he clutched a blade.

“I asked him if he did it and he said yes, and I said why? And he said because [the victim] has killed Muslim people in Muslim countries,” Layou-Kennett said, according to the paper.

One photo showed a blue car apparently used by the men to initially hit the man crashed on the sidewalk.

Boya Dee, a local rapper who tweeted about the attack as it occurred, wrote, “Ohhhhh myyyy God!!!! I just see a man with his head chopped off right in front of my eyes!”

Resident Graham Wilders told the BBC he initially thought that there had been an accident and that the two assailants were trying to aid the victim. “As I drive round the corner, I see the car on the pavement. I thought there has been an accident . . . ’cause as I drive round the corner there was two people leaning over and I thought they were trying to resuscitate him. There was a bloke against the wall . . . another bloke told me they were stabbing him.”

Valentina Soria, a terrorism expert at IHS Jane’s Consulting, said a national security meeting being held so promptly after the attack suggested that the assailants may not have been on the radar of Britain’s intelligence agencies.

“The government is treating this as a very serious incident,” Soria said. “At the end of the day, it is the first successful terrorist attack on the U.K. since the 7/7 bombings.”

“The fact that it was carried out in the middle of the day in a public street is very concerning,” she continued. “There are indications that this was a terrorist attack of jihadist nature. Whether it is homegrown, we can’t yet say. But the fact that they wanted to be filmed indicates that they were seeking public attention. That is the aim, in itself, of the attack.”

Eliza Mackintosh contributed to this report.

Anthony Faiola is The Post's Berlin bureau chief. Faiola joined the Post in 1994, since then reporting for the paper from six continents and serving as bureau chief in Tokyo, Buenos Aires, New York and London.